ORDER VII 



CROCODTLIA 



•211 



Sub-Order 2. PSEUDOSUCHIA. Zittel. 1 



I 'rri/i axillae reduced ; >ut mis very large. External nares paired, placed far 

 forwards; internal nares separate, in about the middle of the palate. Orbits large 

 laterally directed. Parietals and frontals paired ; postorbital distinct. Teeth conical, 

 deeply socketed, confined to anterior half of the jaws. Vertebrae amphiplatyan ; 

 cervical ribs hatchet -shaped, double-headed. Fore-limb slightly shorter limn the 

 posterior ; fifth digit of pes reduced, comprising but a single phalanx. Dorsal a rim in- 

 consisting of a paired series of oblong scutes. 



A'etosaurus, Fraas (Fig. 312). Body lizard-like, longicaudate, with dorsal 

 and ventral armouring of radially ornamented scutes; ventral scutes smaller 

 than the dorsal, and almost square. Skull triangular, acuminate in front. 



Fig. 312. 



A'etosaurus ferratus, Fraas. Upper Reaper ; Heslach, near Stuttgart. Head and anterior portion of trunk, ' '•_.. 

 A, Orbit ; D, Antorbital vacuity ; N, Narial opening ; S, lateral temporal vacuity (after < >. Fraas). 



Antorbital vacuities large, separated from the large external nares by a narrow 

 ascending process of the maxilla. Posterior border of the orbits formed by 

 the postfrontal and postorbital, the inferior border by the jugal. Parietals 

 and frontals similar In form and size. Temporal region imperfectly known. 

 Mandibular rami pierced by a large foramen between the articular and angular. 

 Interclavicle blade-like. Twenty-four complete but slightly crushed in- 

 dividuals are preserved in the Stuttgart Museum, all on a single slab of 

 Stuben Sandstone (Upper Keuper), from Heslach, near Stuttgart. The largest 

 of these has a total length of 86 cm. 



Dyoplax, Fraas. Upper Keuper; Stuttgart. Typothorax, Cope. Trias; 

 New Mexico. 



Ornithosuchus, Newton. Skull pointed in front, very similar to Aetosaurus. 

 Orbits large, supratemporal vacuities small, the lateral ones triangular. Teeth 

 slightly recurved, with finely serrated anterior and posterior cutting edges. 

 Vertebral centra elongated, with very stout neural spine-. Ilium elongated, 

 ischium slender, pubis long and rod-like. Elgin Trias. 0. woodwardi, Newton. 



Erpetosaurus, Newton. Skull narrow and rounded in front. Orbits sub- 

 elliptical, directed upwards and forwards. Supratemporal vacuities round, the 



1 Literature : 



Fraas, <)., Teller Dyoplax arenaceus Wurtt. Jahresh. vol. XXIII. . 18G7. — Aetosaurus ferratus 

 {ibid. vol. XXXIIL), 1877. — Newton, K. T., Reptiles from the Elgin Sandstone (Phil. Trans, vol. 

 CLXXXV.), 1894. 



